title: Endotoxin concentrations within the breathing zone of horses are higher in stables than on pasture.
abstract: Inflammatory airway disease is common in stabled horses, with a prevalence of 17.3% in Michigan pleasure horses. Stable dust is rich in endotoxin, which may induce neutrophilic airway inflammation. Climatological conditions (ambient temperature and relative humidity) may influence endotoxin concentrations in pastures. The aim of this project was to determine if endotoxin levels in the breathing zone of horses in stables were higher than of horses on pasture, and if the endotoxin on pasture was associated with climatological conditions. Endotoxin exposure of six horses that were stabled or on pasture was determined by a Limulus amebocyte lysate assay. Climatological data were obtained from the US National Climatic Data Center. Endotoxin exposure was significantly higher (about 8-fold) in stables than on pasture. On pasture, endotoxin varied widely, despite constant climatological conditions. It was concluded that stabled horses are exposed to higher endotoxin concentrations than horses on pastures. Local endotoxin concentrations may be more important than ambient climatological conditions in determining endotoxin exposure of individual horses.
authors.affiliation: Pulmonary Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, United States.
authors.forename: Annerose
authors.initials: A
authors.lastname: Berndt
authors.affiliation: Pulmonary Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, United States. Electronic address: derksen@cvm.msu.edu.
authors.forename: Frederik J
authors.initials: FJ
authors.lastname: Derksen
authors.affiliation: Pulmonary Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, United States.
authors.forename: N
authors.initials: N
authors.lastname: Edward Robinson
mesh_terms: D016902:Air Pollution, Indoor / Q000009:adverse effects / Q000032:analysis; D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D004391:Dust / Q000032:analysis; D004731:Endotoxins / Q000009:adverse effects* / Q000032:analysis*; D005260:Female; D006734:Horse Diseases / Q000209:etiology*; D006736:Horses; D006799:Housing, Animal; D006813:Humidity; D007249:Inflammation / Q000209:etiology / Q000662:veterinary; D019570:Inhalation Exposure; D008171:Lung Diseases / Q000209:etiology / Q000662:veterinary*; D008173:Lung Diseases, Obstructive / Q000209:etiology / Q000662:veterinary; D008297:Male; D006109:Poaceae; D013696:Temperature
chemical_list: D004391:Dust; D004731:Endotoxins